class fenwick_tree(object):
    def __init__(self, n):
        self.n = n
        self.log = n.bit_length()
        self.data = [0] * n

    def __sum(self, r):
        s = 0
        while r > 0:
            s += self.data[r - 1]
            r -= r & -r
        return s

    def add(self, p, x):
        """ a[p] += xを行う"""
        p += 1
        while p <= self.n:
            self.data[p - 1] += x
            p += p & -p

    def sum(self, l, r):
        """a[l] + a[l+1] + .. + a[r-1]を返す"""
        return self.__sum(r) - self.__sum(l)

    def lower_bound(self, x):
        """a[0] + a[1] + .. a[i] >= x となる最小のiを返す"""
        if x <= 0:
            return -1
        i = 0
        k = 1 << self.log
        while k:
            if i + k <= self.n and self.data[i + k - 1] < x:
                x -= self.data[i + k - 1]
                i += k
            k >>= 1
        return i

    def show(self):
        for i in range(self.n):
            print(self.__sum(i+1) if not i else self.sum(i, i+1),  end=" ")
        print()


N, K = map(int, input().split())
A = list(map(int, input().split()))
if K == 1:
    print(0)
    exit()


Aset = sorted(set(A))
atoi = {a: i for i, a in enumerate(Aset)}
bit_cnt = fenwick_tree(N)
bit_val = fenwick_tree(N)

for i in range(K - 1):
    a = A[i]
    p = atoi[a]
    bit_cnt.add(p, 1)
    bit_val.add(p, a)

ans = 10 ** 18
for i in range(K - 1, N):
    a = A[i]
    p = atoi[a]
    bit_cnt.add(p, 1)
    bit_val.add(p, a)

    mid = bit_cnt.lower_bound((K + 1) // 2)
    a = Aset[mid]
    cost = a * bit_cnt.sum(0, mid) - bit_val.sum(0, mid)
    cost += bit_val.sum(mid + 1, N) - a * bit_cnt.sum(mid + 1, N)
    ans = min(ans, cost)

    a = A[i - K + 1]
    p = atoi[a]
    bit_cnt.add(p, -1)
    bit_val.add(p, -a)

print(ans)